The number of concussions diagnosed in youth athletes has risen considerably over a recent 10-year period, according to researchers from Hasbro Children's Hospital in Rhode Island. Overall, concussions among 14- to 19-year-olds playing organized team sports jumped more than 200 percent from 1997 to 2007, even as participation among 7- to 17-year-olds in the five most popular sports — football, basketball, baseball, soccer, and hockey — decreased by 13 percent.